This invention relates to the art of dispensing a plurality of fluid materials which, when mixed together, react with each other to produce a desired end product, such as an adhesive, potting compound, sealer, encapsulant or the like. The prior art has provided a number of devices in which two reactive materials are kept apart from each other and are mixed together prior to being discharged from the device for their desired end use. However, such prior art devices have failed fully to recognize the importance of exactitude in volumetric metering of the component materials in correct proportions; of complete separation of such components until they are mixed immediately prior to being discharged from the device; and of a highly ordered mixing of the components to insure complete uniformity of the discharged mixture.